Electrostatic precipitators are used for removing particulate matter from a gaseous stream. For example, electrostatic precipitators are commonly found in industrial facilities where the combustion of coal, oil, industrial waste, domestic waste, peat, biomass, etc. produces flue gases that contain particulate matter, e.g. fly ash.
Electrostatic precipitators operate by creating an electrostatic field between at least two electrodes. A first of these electrodes typically has a plate-like shape and is connected to a power supply so as to carry a positive charge. Such an electrode is commonly designated as a collecting electrode or collecting plate. A second of these electrodes is typically embodied in the form of a wire and is connected to said power supply so as to carry a negative charge. Such an electrode is commonly designated as an emission electrode or discharge electrode. Particulate matter in a gaseous stream passing by the second electrode is likewise given a negative charge and is thus attracted to and retained by the positive charge on the collecting electrode. Further information regarding the general construction and operation of an electrostatic precipitator as can be used in conjunction with the teachings of the present disclosure can be found e.g. in U.S. Pat. No. 4,502,872, the entire disclosure of which is hereby incorporated by reference.
Over time, particulate matter accumulates on the collecting electrode, thus diminishing the efficiency with which the electrostatic precipitator can remove particulate matter from the gaseous stream. To combat this problem, it is well known to mechanically hammer against the collecting electrode, a technique known as rapping. This rapping of the collecting electrode causes particulate matter to fall from the collecting electrode into a collecting bin provided therebelow, thus at least partially cleansing the collecting electrode of particulate matter.
Prior art techniques for cleansing the collecting electrode of accumulated particulate matter do not fulfill the expectations of the market as regards, inter alia, the speed and thoroughness of cleansing